(19)
(11) EP 0 716 370 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
16.02.2005 Bulletin 2005/07

(43) Date of publication A2:
12.06.1996 Bulletin 1996/24

(21) Application number: 95117739.3

(22) Date of filing: 10.11.1995
(51) International Patent Classification (IPC)7G06F 3/06, H04N 7/173
(84) Designated Contracting States:
DE FR GB

(30) Priority: 06.12.1994 US 350364

(71) Applicant: International Business Machines Corporation
Armonk, N.Y. 10504 (US)

(72) Inventors:
  • Kouloheris, Jack L.
    Mohegan, New York 10547 (US)
  • Kumar, Manoj
    Yorktown Heights, New York 10598 (US)

(74) Representative: Teufel, Fritz, Dipl.-Phys. et al
IBM Deutschland Informationssysteme GmbH, Patentwesen und Urheberrecht
70548 Stuttgart
70548 Stuttgart (DE)

   


(54) A disk access method for delivering multimedia and video information on demand over wide area networks


(57) A method and apparatus for delivering multimedia video data from a server (host processor) to a plurality of clients connected to a communications network. More specifically, with this invention, preprocessed video and multimedia data packets are striped across disks in units of fixed playback time, even if such units result in variable length stripes. To deliver multiple video or continuous media streams, the disks in the array are accessed simultaneously so that at any given instance, different disks are accessing the video or multimedia data for different streams. Access to the disks for reading the continuous media files is scheduled periodically, with the period equal to the back time of the stripes. Because each disk read command retrieves data for a fixed play back time, if the first read command for a continuous media stream request can be scheduled to complete on a disk within a playback time, all subsequent read commands are also guaranteed to not interfere with read commands of other streams. Data is delivered directly from the disk array to the communication network by a stream controller without being sent to the host system. Disk storage is utilized efficiently by allocating disk space in units of cylinders and storing the variable size stripes of video in packed format.







Search report